Test CEE Sewa
  1. Cytology and Cell Biology 

    Cytology 

     

    Cell Biology (Modern Cytology) 

    1. Cytology includes the study of  

      1. Cell organelles (living part of cell) and  

      2. Cell inclusions (Non-living part of cell) only. 

    1. Cell Biology (Modern Cytology) includes study of 

      1. Cell organelles 

      2. Cell inclusions along with 

      3. Physiology of cell 

      4. Chemistry of cell and  

      5. Genetic of cells 

    1. Cytology deals form and structure of cell. 

    1. Cell biology deals with Structure and Function of cell. 

    1. Robert Hooke is the father of Cytology. 

    1. Swanson is the father of Cell biology or Modern Cytology. 

  2. Check check 

  3. History 

    1. Robert Hooke:  

      1. Term "Cell" was coined by him in 1665. 

      2. Discovered cell form outer bark of Quercus suber. (Cork Oak) 

      3. Actually it was Cell wall, Dead cell, Attached cell. 

      4. Robert Hooke published his finding in a book 📙, Micrographia. 

    2. A.V. Leeuwenhoek: 

      1. Father of Microscopy 

      2. Discovered living cell and is free cells. 

  4. Cell Theory 

    1. Cell theory was proposed by Schwann (German Zoologist) and Schleiden (German Botanist). 

      1. Note: 1st idea 💡 of cell theory was given by Dutrochet by boiling the leaf of Mimosa pudica in nitric acid and separated the cell. 

    2. It states that all living being consists of cell and is the smallest structural and functional unit of life.  

    3. Cell theory was extended by Rudolf Virchow. 

      1. Rudolf Virchow proposed "Law of cell lineage" stated "omnis cellula e cellula" meaning all cells are originated from pre-existing cells only by reproduction. 

      2. Cell principle/ Cell doctrine/ Modern or modified cell theory = Cell theory + Cell lineage. 

    4. Exceptions of cell theory 

      1. Virus = Obligate parasites, Sub-cellular in nature (Major exception) 

      2. Vaucheria (Algae) = Multinucleated 

      3. Rhizopus, Mucor (Fungi) = Multinucleated 

        1. Rhizopus 

           

          Mucor  

      4. Paramecium (Protista) = Binucleate/ multinucleated 

      5. Opalina (Protist) = Multi-nucleated 

  5. Cell size 

    1. The normal cell size is 0.2 μm to 20 μm. 

    2. The unit of measurement in micron (μm) in light microscope and is angstron (Å) in electron microscope. 

    3. Factors affecting cell size are: 

      1. Cell sizeChromosome number
         

      2. Cell sizeSize of Chromosome
         

      3. Cell size1Metabolic activity  (Smaller cells are metabolically active)
         

      4. Cell size1Nucleocytoplasmic ratio (Nucleocytoplasmic ratioMetabolic activity)
         

      5. Cell size1Surface area of the cell per unit volume (Smaller cells have greater surface area per unit volume)
         

    4. Smallest cell 

      1. Smallest cell = Mycoplasma gallisepticum / PPLO(Pleuro pneumonia like organism)/ Joker of Plant Kingdom 

        1. Without cell wall 

        2. Plant 🌱 diseases caused by Mycoplasma 

          1. Bunchy top of Papaya 

          2. Little leaf of Brinjal 

          3. Clover🍀 dwarf 

          4. Mulberry dwarf 

      2. Smallest cell with cell wall = Bacteria (Dialister pneumosintes) 

      3. QuestionSmallest animal cell = Human sperm cell 

    5. Largest and Longest cell 

      1. ImportantLargest prokaryotic cell: Spirillum volutant 

      2. Animal cell 

        1. Largest cell = Ostrich egg cell 

        2. Longest cell = Nerve cell 

      3. Plant cell 

        1. Largest cell = Acetabularia 

          1.  
            1. Unicellular 

            2. Uninucleate 

            3. Belongs to green algae  

            4. Umbrella shaped algae 

        2. ImportantLongest cell = Fibre of Ramie (Boehmeria nivea) 

          1.  
  6. Cell Dividing capacity 

    1. Cellular totipotency (Latin: Totus = all; potens = power) 

      1. Capacity of individual or single, nucleated, living vegetative plant cell to regenerate whole plant. 

      2. Idea of cellular totipotency was firstly given by Haberlandt. 

      3. Phenomenon of cellular totipotency was proved experimentally by Steward and his co-worker. 

        1. He used phloem tissue from roots of carrot as an explant. 

        2. Used coconut milk in his experiment as liquid media. 

          1. Coconut 🥥 milk naturally contain cytokinin which induce cell division. 

            1. So, cytokinin(zeatin) is also called coconut milk factor. 

            2. Zeatin/ Cytokinin/ Kinetin is also rich in immature maize grain. 

    2. Pluripotency: 

      1. Pluripotency is the potential ability of an animal cell to develop into any type of the cell in the animal body but not into whole animal. 

      2. Stem cells are only totipotent in animal. 

    3. Cell Ghosts: 

      1. Erythrocyte empties; named so because they are difficult to observe under light microscope due to absence of contents. 

      2. Erythrocyte contents come out when a drop of blood is placed in water. 

      3. It causes rupturing of erythrocytes or haemolysis. 

  7. Cell types on the basis of Nucleus. 

    1. Akaryotic cell 

      1. A denucleated cell 

      2. E.g. 

        1. Mature mammalian RBC 

        2. Sieve tube cell 

    2. Prokaryotic cell 

    3. Mesokaryotic cell 

      1. Nucleus with Nuclear membrane but lacks histone protein in DNA and nucleolus in nucleus. 

      2. Cell division occurs by dinomitosis. 

      3. Rest of characters are same to eukaryotic cell. 

      4. E.g: Dinoflagelltes 

    4. Eukaryotic 

    5. S.N. 

      Prokaryotic cell 

       

      Eukaryotic cell 

      1. Cell wall 

      Cell wall when present is non-cellulosic and made up of peptidoglycan (murein) and lipids. 

      Cell wall present is of Cellulose or Chitin. 

      Cell membrane 

      Site of aerobic respiration is mesosome (Cell membrane) because mitochondria is absent. 

      Site of aerobic respiration is Mitochondria. 

      1. Membrane of cell organelles 

      Membrane bound cell-organelles are absent. 

      So, called single envelop system. 

      Membrane bound cell organelles are present. 

      So called double envelop system. 

      1. Envelope system 

      Has 1-envelope system. 

      2-envelop system. 

      1. Nucleus 

      False Nucleus/ Incipient nucleus/ Prokaryon/ Prochromosome/ Diffused fibrillar nucleus/ Genophore/ Nucleoid 

      • Nuclear membrane, Nucleoplasm and Nucleolus absent 

      True nucleus/ well organized 

      • Nucleus with nuclear membrane, nucleoplasm and nucleolus. 

      1. DNA 

      DNA 

      1. Lies in Cytoplasm 

      2. Double stranded 

      3. Circular 

      4. Non-repetitive 

      5. Without histone proteins 

      6. Folded with the help of RNA and polyamines. 

      DNA  

      1. Lies in Nucleoplasm 

      2. Double stranded 

      3. Linear 

      4. Repetitive 

      5. Presence of Histone protein 

      6. Folded with the help of Histone protein 

      1. Histone protein 

      Histone protein absent in DNA.  

      • But has polyamine as basic protein which neutralize the anionic charge of inter nucleotide phosphate of DNA. 

      Histone protein is present in DNA.  

      • It neutralizes the anionic charge of inter nucleotide phosphate of DNA. 

      • Histone protein is positively(+) charged 

      DNA:RNA ratio 

      DNA:RNA ratio = 1:2 

      DNA:RNA = 1:1 

      A+TG+C
       

      A+TG+C=0.88 (i.e., G+C is higher)
       

      A+TG+C=1.52 (i.e., G+C is less)
       

      Ribosomes 

      Ribosomes: 70 s type 

      Ribosome: Both 70s and 80s (80s main type) 

      Microtubules and spindle fibres 

      Microtubules and spindle fibres absent 

      Microtubules and spindle fibres present. 

      Cilia and flagella 

      ImportantCilia and flagella if present are single stranded and made up of flagellin protein. 

      ImportantCilli/ flagella when present are 11 stranded and shows 2+9 arrangement and made up of tubulin protein. 

      Cell division 

      Cyclosis, mitosis, meiosis absent and Amitosis is common. 

      Cyclosis, Mitosis, Meiosis present and Amitosis rarely found in yeast. 

      Examples 

      1. Monera 

        1. Bacteria 

        2. Cynobacteria/ BGA 

        3. Arachaebacteria 

        4. Mycoplasma 

        5. Chlamydia 

        6. Rickettsia 

      1. Fungi 

      2. Protist 

      3. Euglena 

      4. Plants and  

      5. Animals 

       

      Special 

      • Most extensively studied prokaryote is E. coli. 

      • ImportantChlamydia and Rickettsia have both RNA and DNA as nucleic acid and are connecting link between virus and bacteria. 

      Eukaryotic cell differ from prokaryotic cell in having presence of cistrons. 

  8. Difference between Plant 🌿 cell and Animal cell 

    1.  

    2. S.N. 

      Plant cell 

       

      Animal cell 

       

                

       

      Have  

      1. cell wall (Main differentiation) 

      2. Plastids 

      3. Large central vacuole 

       

       

      QuestionChromosome with centriole and and lysosome absent. 

       

       

      QuestionMitosis/ meiosis is Anastral type. 

      It is Astral or Amphiastral type. 

       

      Inorganic crystals are common in cytoplasm. 

       

       

      Sphaerosome, Glyoxisome, Lomasome are present. 

       

       

      Cytokinesis by cell plate. 

      Cytokinesis is but furrowing. 

       

      Reserve food is Starch. 

      Reserve food is Glycogen. 

       

      Plant cell don't burst in hypotonic solution due to presence of cell wall. 

      RBC gets burst because it has no cell wall. 

       

      All nucleated cells are totipotent. 

      Fertilized egg and Stem cells in blastocyst are totipotent. 

  9. Cell Organization 

    1. Cell wall 

      1. Common in plants; also in bacteria, cyanobacteria. 

      2. It is non-living. 

      3. Constituents 

        1. Plant cell wall is made up of 

          1. Cellulose  

            1. β-D glucose 

          2. Hemicellulose and 

            1. Arabinose 

            2. Mannose 

            3. Xylose 

            4. Galactose, etc 

          3. Pectin 

            1. Galactose 

            2. Galacturonic acid and  

            3. Arabinose 

        2. In bacteria and cyanobacteria, cell wall is made up of 

          1. Murin/ 

          2. Mucopeptide/ 

          3. Peptidoglycan 

            1. Polysaccharide part of peptidoglycan is the polymer of N-acetyl glucosamine(NAG) and N-acetyl muramic acid(NAM). 

        3. In fungi, cell wall made up of Chitin/ fungal cellulose. 

          1. QuestionChitin

            (C22H54N4O21)n 
            is polymer of N-acetyl glucosamine(NAG).  

            1. NAG is amino acid. 

      4. Cell wall is 

        1. Porous 

        2. Permeable 

        3. Inert 

        4. Hydrophilic 

        5. Semitransparent 

        6. Protective covering secreted by Cytoplasm. 

      5. Plant cell without cell wall is 

        1. Mycoplasma, 

        2. Gametes, 

        3. Zoospores, 

        4. Slime moulds (Myxomycetes). 

      6. Cell wall formed during cytokinesis from vesicles of ER and Golgi bodies. 

      7. Layers of Cell wall 

        1.  

           

           

        2. In higher plants, cell walls consists of different layers 

        3. Middle lamellae: 

          1. Outermost layer of cell wall. 

          2. Layer between cell wall of two cell is Middle lamellae. 

          3. It is cementing layer that joins 2 adjacent plant cells together. 

            1. It contains cementing material Ca-pectate and Mg-pectate. (Mainly Ca-pectate) 

            2. ImportantRetting of fibres and ripened fruit becomes soft due to dissolution of middle lamellae (dissolution of Ca-pectate) and dissolution is brought by Pectinase enzyme. 

              1. Retting of fibres 

                 

                 

                 

                 

                 

                 

                 

                 

          4. First layer to be formed during cytokinesis by vesicles of Golgi bodies and ER. 

            1. During cytokinesis, vesicles of golgi bodies and spindle protein come to the equator called Phragmoplast. 

            2. Phragmoplast(Precursor molecule) form Cell plate. 

            3. Cell wall is formed from cell plate. 

            4.  

              Vesicles of GB+Spindle proteinPhragmoplastCell plateCell wall
               

          5. Middle lamellae is totally absent in all unicellular plant and all fungi. 

          6. QuestionGrows by 

            1. Intussusceptions or 

              1. Primary wall stretched and materials of secondary wall are deposited 

            2. Apposition 

              1. Materials of secondary wall are deposited in the form of thin layer. 

        4. Primary cell wall: 

          1. Elastic in nature 

          2. Unipartite (Single layer) 

          3. It is found universally in all cells having cell wall. 

          4. Lies inner to middle lamella. 

          5. Made up of  

            1. Cellulose (β-D glucose unit), 

            2. Hemicellulose and  

            3. Pectin roughly in equal amount. 
              Note: Starch is formed by α-D glucose unit. 

          6. Lignin is never found in primary cell wall but may have Silica, Wax, Cutin, etc. 

          7. Primary cell wall is common in Parenchyma and Meristematic cells. 

          8. Grows by Intussusception. 

        5. Secondary cell wall: 

          1. Thick 

          2. Inelastic in nature 

          3. Present inner to primary cell wall. 

          4. Tripartite namely 

            1. S1 

            2. S2 and  

              1. S2 is thickest layer. 

            3. S3 

          5. Developed by Apposition. 

          6. Pits is common. 

          7. Provides mechanical strength, stiffness and hardness to cell. 

          8. Made up of Cellulose (high), sometimes hemicellulose and additionally by: 

            1. Cutin (Waxy substance) 

              1. Found in epidermis and its continuous layer is called Cuticle. 

                1. Cuticle is thick layered by Xerophytes. 

                2. Cuticle is thin layered in mesophytes. 

                3. Cuticle is absent in hydrophytes. 

            2. Suberin:  

              1. In Cork cells and Endodermis. 

              2. It makes the cell impermeable. 

              3. It checks evaporation of water. 

              4. It is mixture of fatty acids. 

            3. Pectin 

              1. In Collenchyma 

              2. Provides elasticity 

            4. Lignin 

              1. In xylem vessels, Sclerenchyma, Tracheids (Dead cells) 

              2. Lignin is permeable to water and lignified cells are thick-walled and dead. 

              3. Gives highest rigidity. 

            5. Wax: On floating leaves 

            6. Silica: 

              1. Deposited on the cell wall and gives rough touch. 

              2. E.g.: Equisetum (Horsetail) 

            7. Mucilage 

              1. Chemically, it is complex carbohydrate. 

              2. Slimy substance, slippery to touch. 

              3. Due to this, the cells can withstand extreme temperature. 

              4. E.g.: 

                1. Aloe vera 

                2. Hibiscus 🌺 (China rose) 

        6. Tertiary cell wall 

          1. ImportantRemember for laterSometimes S3 of secondary wall is called as tertiary wall when it contains Xylon(Polymer of D-xylose) and Mannon. 

          2. Thick and warty in appearance. 

          3. E.g.: Tracheids of gymnosperm  

      8. Cell to cell conduction system 

        1. S.N. 

          Symplasm (Living sytem)/ Plasmodesmta 

           

          Apoplasm (Non-living system)/ Pits 

           

          Plasmodesmata are living cytoplasmic strands which establish connections between adjacent plant cells. 

          Unthickened area in cell wall where secondary wall is not produced is called as pit. 

           

          Through the plasmodesmata, all the protoplasts of a living system are linked to form a continuous system called symplasm. 

          Dead cells are interconnected by means of pits and form Apoplasm. 

           

          Plasmodesmata is modification of cell membrane and found only in multicellular plant. 

          • Pits are found only in secondary wall. 

          • Pit consists of Cavity and Pit membrane. 

            • Pit membrane is middle lamella + primary cell wall (but mainly primary cell wall) 

          Types of pits 

          Simple pits 

           

          Bordered pits (Cavity flask shaped) 

          1. Are uniform in diameter. 

          2. Found in Angiosperms. 

          3. It lacks pit chamber and torus. E.g.: Companion cells and Sieve tubes. 

          1. Cavity flask shaped. 

          2. Found in Gymnosperms. 

          3. It contains pit chamber and torus. 

            1. Torus is swollen portion of pit membrane and acts as valve. E.g.: Vessels and Tracheids. 

          Note: 

          • Sclerenchyma fibre has simple pits as well as bordered pit. 

          • QuestionAspirated pit is a non-functional pit in which pit aperture is blocked permanently by torus. 

      9. Cell constituents 

        1. Cellulose is most abundant carbohydrate of Biosphere. 

          1. Cotton contains highest amount of Cellulose(90%) in biosphere. 

        2. Chitin is the second most abundant carbohydrate. 

        3. βD Glucose    600   Cellulose   100   Micelle   20   Microfibril  250   Macrofibril
           

        4. Structural unit of Cell wall are 

          1. Micelle 

          2. Microfibril 

          3. Macrofibril 

    2. Cell coat/ Glycocalyx 

      1. In animal cell, cell wall is absent and outermost covering is called Cell coat 🧥 or Glycocalyx. 

      2. ImportantCell coat is made up of Oligosaccharides and terminal sugar of oligosaccharide is Sialic acid. 

        1. The layer of carbohydrate is oligosaccharide in animal cell helps in cell to cell recognition. 

      3. Glycocalyx = Glycoprotein +Glycolipid.
         

        1. Glycoprotein and Glycolipid help in Site recognition. 

        2. So, Glycocalyx is site of Cell recognition. 

        3. Glycocalyx makes the cell membrane asymmetric. 

      4. Note: In cell Recognition: Oligosaccharide > (Glycoprotein + Glyolipid) 

    3. Protoplast 

      1. Plasma membrane/ Cell membrane/ Plasmalemma 

        1. Cell membrane is  

          1. Thin, 

          2. Elastic, 

          3. Living,  

          4. Selectively or Differentially permeable membrane. 

        2. Made up of phospholipid (common) and protein. 

            1. Head = Hydrophilic 

            2. Tail = Hydrophobic 

             
          1. Forms of Lipid in Cell membrane 

            Forms of Protein in Cell membrane 

             

            Forms of Carbohydrate in cell membrane 

            • Fluidity and Elasticity of cell membrane depends upon lipid. 

            1. Phospholipid 

              1. Frame work molecule of cell membrane 

              2. Phospholipid is amphipathic molecule, because it shows double property, hydrophilic as well as hydrophobic. 

              3. Phospholipid membrane is always bilayered. 

            2. Glycolipid 

            3. Cholesterol 

            • In general, Protein > Lipid in cell membrane but in Myelin sheath Lipid(75%) > Protein (25%). 

            1. Extrinsic or Peripheral protein (25%) = Can easily be exuded out 

            2. Intrisic or Integral protein (75%)     

             

            1. Glycolipid 

            2. Glycoprotein 

             

            1. Remember for laterImportantArginine and Lysine are amino acids found in cytoplasmic membrane. 

             

        3. Thickness of Plasma membrane is 75 [Equation]. 

        4. Plasma membrane+Organelle membrane=Biological membrane
           

        5. Different Models of Cell membrane 

          1. Trilamellar model or Sandwich model 

            Unit membrane model 

             

            Fluid Mosaic Model 

             

             

            1. Proposed by Danielli and Davson. 

            2. Accordingly, plasma membrane consists of 3 layers. 

              1. Outer: Protein 

              2. Middle: Bilayered phospholipid 

              3. Inner: Protein 

            3. QuestionProtein is Globular type. 

            4. Sequence of Lipid and Protein is 

              PLLP.
               

            1. Proposed by Robertson. 

            2. Unit membrane model is similar to Trilamellar model except nature of Protein i.e., Fibrillar type. 

            3. Sequence of lipid and Protein is

              PLLP.
               

               

            1. Proposed by Singer and Nicolson. 

            2. Latest and most widely accepted model. 

            3. QuestionThis model is based on freeze etching/ fracture technique. 

            4. QuestionThis model differs from trilamellar model and unit membrane model in the arrangement of protein. 

              PLPL      OR       LPLP.
               

            5. "Protein iceberg in sea of lipid" meaning lipid form continuous layer and protein molecules are randomly arranged. 

            6. Proteins are 

            • Extrinsic (surface, 25%) 

            • Tunnel (In between extrinsic and intrinsic) 

            • Intrinsic (Inner, 75%) 

            1. All carrier proteins are intrinsic protein. 

            2. QuestionLipid and proteins in the membrane are held together due to hydrophobic attraction. 

            3. ImportantRemember for laterThe rotational movement of lipid molecule is called Flip-flop mechanism. 

        6. Functions of Plasma membrane: 

          1. QuestionPlasma membrane controls passage of material in and out of cell with the help of Ca2+ and CAMP(Cyclic Adenosine Monophosphate). 

          2. Exchange of gases like CO2 and O2 is possible through membrane. 

          3. Plasma membrane also show bulk transport. 

            1. Active transport requires energy as well as carrier protein. 

            2. Passive transport requires neither energy nor carrier protein. 
              Exception: Faciliated diffusion is a passive transport which doesn't require energy but requires carrier protein. 

        7. Junction complex 

          1. Junction complex is found only in multicellular organism for cell adhesion. 

          2. It is of following types. 

          3. Plasmodesmata 

            1. Desmosome 

            1. Tight junction 

            1. Gap junction 

            1. Interdigitation 

             
            1. Terminal bar 

            • Plasmodesmata are living cytoplasmic strands which establish connections between adjacent plant cells. 

            • Plasmodesmata is modification of cell membrane and found only in multicellular plant. 

            acts like a spot weld between two adjacent animal cells. 

            watertight seal between two adjacent animal cells 

            channels between adjacent animal cells 

            Interwoven processes 

            unresolved group of junctional complexes that attach adjacent epithelial cells on their lateral surfaces 

             

             

             

             

             

             

             

        8. Modification of cell membrane: 

          1. A) Mesosome 

            ImportantB) Lomasome 

            ImportantC) Lamellosome 

             

            D) Microvilli 

             

             

             

             

            • Infoldings of cell membrane in bacteria (Gram +ve) 

            • Helps in respiration and Cell division. 

            • Lomasome is present in between cell membrane and cell wall and thus called as extracellular cell organelle. 

            • It is found only in fungus 

            • ImportantDefinitionIt helps in proliferation and elongation of cell wall for diffusion. 

            • Infolding of cell membrane in Blue Green Algae. 

            • Helps in expansion of cell wall. 

            • Finger like evagination (outfolds) in cells of digestive tract for ultra-absorption of liquids. 

      2. Protoplasm 

        • About protoplasm 

          1. Purkinje coined the term Protoplasm. 

          2. Huxley defined it as "Physical basis of life" because all the processes of life occur in protoplasm. 

          3. Best material to study protoplasm is Slime moulds (Because of absence of Cell wall). 

          4. Protoplasm is the highly organised and most active chemical system of nature with maximum energy conversion. 

          5. Living beings differ from non-living in having protoplasm. 

          6. Protoplasm constituent 

            1. Highest % of water is present in protoplasm (75-85%). 

              1. The major inorganic constituent of protoplasm is water. 

            2. Constituent elements of protoplasm by weight: 

              1. Oxygen = 62% (HIGH) 

              2. Carbon = 20% 

              3. Hydrogen = 10% 

              4. Nitrogen = 3% (LOW) 

            3. The ratio of inorganic to organic substance in cell is 1:9. 

          7. Protoplasm exists in two different forms 

            (Sol (inner)Gel (outer))(Liquid like)           (Jelly like)
             

            1. Sol-gel interconversions is because of colloidal nature of protoplasm. 

            2. Outer gel like called ectoplast (plasma gel) and inner sol part called endoplast (plasma sol). 

            3. The conversion of plasmasol into plasmagel is a physio-chemical phenomenon. 

            4. Cyclosis occurs in endoplast region. 
              2 types: 

              1. Rotation: Movement in one direction (Clockwise/ anticlockwise) around vacuole inside a cell  

                1. Ex: Hydrilla, Vallisnaria. 

              2. Circulation: Movement is in different direction around vacuole inside the cell 

                1. E.x: Tradescantia 

            5. Brownian movement, Tyndal effect, Cyclosis and Amoeboid movement in cells are due to colloidal nature of protoplasm. 

            6. Protoplasm coagulates at above 60o or when treated with concentrated acids/bases. 
              Notes: Enzymes denatured at high temperature and inactivated at very low temperature. So, optimum temperature is required for the functioning of enzyme. 

            7. Deutoplasm is the non-living substance formed by the protoplasm during metabolism. E.g., liquid droplets, yolk, etc. 

        1. Cytoplasm 

          1. Cell organelles 

            1. Organenelle bounded by Triple membrane 

              1. Transosomes 

                1. Transosome is found in ovarian follicle of bird. 

                2. It takes part in synthesis of yolk (vitellogenesis). 
                  Note: In other anima, Vitellogenesis takes place with the help of Golgi bodies(manily) + ER + microfilaments. 

            2. Organelle bounded by Double membrane 

              1. Plastid 

                1. Discovered and term given by Haeckel. 

                2. Mainly found in plants and certain protist, absent in fungi. 

                3. Involved in formation and storage of carbohydrate. 

                4. Usually 3 types, on the basis of Pigments. 

                5. Leucoplast: 

                  1. Largest plastid. 

                  2. Usually found in underground parts. 

                  3. Function: Storage of reserve food material. 

                    1. 3 types on the basis of nature of food stored: 

                    2. Amyloplast = Stores Starch = E.g.: Potato, Rice, Wheat 

                    3. Proteinoplast/ Aleuronoplast = Stores Protein = E.g.: Maize 

                    4. Elaioplast/ Oleosome/ Lipoplast = Stores oil/fat = E.g.: Ricinus (Castor seed)(Dicot with Endosperm) 

                6. Chromoplast: 

                  1. 2nd largest plastid. 

                  2. Chromoplast is coloured plastid (other than green). 

                  3. Have fat soluble carotenoids to provide colour to fruits, seeds and flowers. 

                  4. Formed by  

                    1. Chloroplast (Due to replacement of chlorophyll pigment by other coloured pigment) 

                      1. Green tomato changes into Red tomato 🍅 due to replacement of chlorophyll by pigment Lycopin. 

                      2. Green chilies change to Red chilies due to replacement of chlorophyll by pigment Capsanthin. 

                    2. Leucoplast (Due to development of coloured pigment) 

                      1. Carrot 

                  5. Other coloured plastids are: 

                    1. Phaeoplast: It is brown plastid. E.g: Brown algae 

                    2. Rhodoplast: It is red plastid. E.g: Red algae 

                7. Chloroplast: 

                  1. Discovered by Sachs but named chloroplasts by Schimper. 

                  2. Chloroplast is green plastid. 

                  3. Function: Formation of carbohydrate and Store starch temporarily. 

                  4. Also called Kitchen of cell, Photosynthetic apparatus, Autoplasts. 

                  5. Common in all photosynthetic organism except photosynthetic bacteria and cyanobacteria (BGA). 

                    1. In photosynthetic bacteria and Cyanobacteria pigments are found in Chromatophore (Scattered thylakoids). 

                  6. Shape of chloroplast: 

                    1. Shape generally Discoid/ Oval/ Tablet 💊 shaped or Biconvex. 

                    2. Cup 🥤 shaped = Chlamydomonas 

                    3. Spherical shaped = Chlorella 

                    4. Spiral/ Ribbon shape/ Scalariform = Spirogyra 

                    5. Girdle/ Ring/ Collar/ Horse 🐎 shoe shaped = Ulothrix 

                    6. Reticulate/ Net like = Oedogonium 

                    7. Stellate or Star shaped = Zygnema (Double star) 

                    8. Discoid shaped = Vaucheria, Chara 

                  7. No. of chloroplast 

                    1. Single chloroplast = Chlamydomonas and Chlorella 

                    2. Single chloroplast in each cell = Ulothrix 

                    3. Double chloroplast in each cell = Zygnema 

                    4. No. of chloroplast is maximum in mesophyll cells of leaf. 

                  8. Structure of Chloroplast 

                    1. Chloroplast is differentiated into Grana and Stroma. 

                    2. Grana 

                      1. Grana is the site for Light reaction. 

                        1. Note:  

                        2. Agranal chloroplast is common in algae and bundle sheath chloroplast of C4 plants. 

                        3. Agranal chloroplast in which thylakoids are not stacked is called Lamellar chloroplast. 

                        4. Thylakoids 

                        5. Thylakoids (baggy trousers) are structural unit of chloroplast, whereas 

                          1. Quantasomes 

                          2. Quantasomes are functional unit of chloroplast. 

                          3. Photosynthetic pigments are present in membranes of thylakoids at specific areas called Quantasomes. (280 pigments) 

                            1. Quantasomes of Eukaryotes consists 230 chlorophyll molecules (160 chl-a +70 chl-b) and 50 carotenoids molecules. 

                            2. Quantasomes of Prokaryotes consists of only 50 chlorophyll molecules. 

                        6. Grana are interconnected by means of Stroma lamellae or Fret membrane or Intergranal thylakoid. 

                         

                    3. Stroma 

                      1. Stroma is the ground substance of chloroplast. 

                      2. Stroma includes: 

                        1. Matrix 

                          1. Matrix contains enzymes of dark reaction/ CO2 fixation. 

                        2. DNA +ribosome 

                  9. Blue green algae lacks chloroplast, site of photosynthesis is photosynthetic lamellae. 

              2. Mitochondria 

                  1. Power house of Cell or Electric house of Cell or Cellular furnace or ATP mills. 

                  2. Discovered by Kolliker in striated muscle of insects. 

                  3. Benda used the term mitochondria. 

                  4. Altman gave the term "Bioplast" for mitochondria. 

                  5. Size varies from 0.5 to 1 μm. 

                  6. Absent in all prokaryotes, anaerobic eukaryotes and present in all aerobic eukaryotes except mature mammalian RBC, cancareous cell, sieve tube of phloem. 
                    Note: RBC at maturity obtains energy of glycolysis. 

                  7. Structure of Mitochondria 

                   
                  1. Membranes 

                    1. Outer membrane is permeable due to porins (special protein function as channel for entry and exit of protein) whereas inner membrane in permeable. 

                      1. ImportantOuter mitochondrial chamber contain enzyme adenylate kinase. 

                    2. Inner membrane has infolding called Cristae (in animals) and tubuli or microvilli (in plants). 

                      1. Cristae is the site of oxidation-reduction. 

                      2. Inner membrane/ Cristae bear electron transport chain and tennis racket like particles called Oxysomes. 

                      3. Oxysomes are called Functional unit of Mitochondria. 

                      4. Oxysome is differentiated into 

                        1. Head 

                          1. Also called F1 particle. 

                          2. Contains enzyme ATPase. 

                          3. ATPase helps in final step of ATP syntheses. 

                        2. Stalk 

                        3. Base 

                          1. Also called Fo particle. 

                          2. ETS (Electron transport system) takes place. 

                          3. It has proton channels. 

                            1. When 2 protons pass through proton channel, 1 ATP is released. 
                              But, according to new concept, it is accepted as 1 ATP is released when 3 electrons are passed through proton channel. 

                  2. Matrix 

                    1. About 70% of total cell enzymes are found in mitochondria. 

                    2. Enzymes of Kreb's cycle are found in matrix of mitochondria except 'Succinic dehydrogenase' which remains bounded with Inner membrane of mitochondria. 

                    3. Enzyme for fatty acid synthesis, amino acid synthesis, etc. are also found in matrix of mitochondria except "ATPase" and "Cytochrome oxidase". (Located in inner membrane of mitochondria). 

                    4. Matrix of mitochondria is rich in Mn. 

                1. To DoThe process of ATP synthesis in mitochondria is called Oxidative Phosphorylation which is O2 dependent but light independent. 

                2. To DoMitochondria of a cell are collectively called Chondriome. 

                3. To DoMitochondria whose outer membrane is removed are called Mitoplasts. 

                4. To DoAcristate (no cristae) mitochondria is found in spermatid. 

                5. To DoFunction 

                  1. To DoPetite character in yeast is due to mitochondrial inheritance. 

                  2. To DoMitochondria helps in elongation of fatty acid. 

                  3. To DoIt forms the middle piece of sperm. 

            3. Organelle bounded by Single membrane 

              1. Endoplasmic reticulum 

                1.  

                   

                   

                   

                  Protein_translation.gif

                   

                   

                  1Nucleus  2Nuclear pore  3 Rough endoplasmic reticulum (RER)  4 Smooth endoplasmic reticulum (SER)  5Ribosome on the rough ER  6Proteins that are transported  7 Transport vesicle  8Golgi apparatus  9 Cis face of the Golgi apparatus  10 Trans face of the Golgi apparatus  11 Cisternae of the Golgi apparatus 

                2. Firstly observed by Porter from liver cells. 

                3. ER is also called  

                  1. Working bench of cell 

                  2. Pipeline of cell or 

                  3. Endoskeleton 

                  4. Organelle of Membrane factory 

                  5. Organelle of Detoxification  

                4. Extensively developed in Pancreas, Liver, Digestive gland, Fibroblast and poorly developed in sperms, meristematic cells, etc. 

                5. Unit membrane structure, bounded by single trilaminar lipoprotein membrane. 

                6. Not visible under light microscope. 

                7. Absent in 

                  1. All prokaryotic cell 

                  2. Some eukaryotic cells like 

                    1. Mammal's RBC 

                    2. Egg 

                    3. Embryonic cell 

                    4. Monocyte of WBC 

                  3. Note: ER is poorly developed in rapidly dividing cell. E.g: Meristematic cells 

                8. It is made up of 

                  1. Cisternae (Flattened sac/bag) 
                    Note: Cisternae is not parallel in ER but they are parallel in Golgi bodies. 

                  2. Tubules 

                  3. Vesicles 

                9. ER continues from nuclear membrane to cell membrane. 

                10. ER continue from one cell to another by plasmodesmata is called Desmotubule. 

                11. ER forms more than 50% of total membranes in the eukaryotic cells and occupies 10% of total cell volume. 

                12. ER is of 2 types: 

                  1. Rough Endoplasmic reticulum 

                     

                    Smooth Endoplasmic Reticulum 

                    1. Forms

                      23rd
                      of total ER. 

                    2. 80s ribosomes are attached by their largest subunit with the help of glycoprotein called Ribophorin. 

                    3. Mainly consists of Cisternae and a few tubules. 

                    4. Arises from nuclear membrane. 

                    5. Function: Protein synthesis and Glycosylation. 

                    1. Forms

                      13rd
                      of total ER. 

                    2. Lacks attached ribosomes. 

                    3. Mainly consists of network of tubules and vesicles. 

                    4. Arises from RER. 

                    5. Function: Lipid metabolism. 

                13. The broken part of ER (RER) produced during ultracentrifugation is called Microsome. 

                14. Part of cytoplasm which is basophilic due to presence of RER of ribosome is known as ergastoplasm. 

                15. Nissl's granules is modification of RER/ Ribosome. 

                  1. Nissl's granules are rich in RNA followed by protein. 

                16. RER without ribosomes are called Transitional ER. 

                17. SER present in epithelial cell of retina eyes is called Myloid bodies (responsible for photoreception). 

                18. Annulate lamellae are the precursor of ER. 

                19. Special type of ER in skeletal muscle cells are called Sarcoplasmic reticulum (involves in release of Ca++). 

                20. Ca++ helps in muscle contraction in fusion of vesicles. 

                21. Microbodies called sphaerosome are formed by SER. 

                22. RER in association with golgi complex gives rise to Lysosome. 

                23. SER in liver cell helps in 

                  1. Detoxification of harmful chemicals 

                  2. Glycogenesis (formation of glycogen from glucose) + Glycogenolysis (Breakdown of glycogen into glucose) 

                24. Function of ER 

                  1. It provides mechanical support due to presence of microtubules and thus called as Endoskeleton of cell. 
                    Note: Structural skeletal structure of cells i.e., cytoskeletal of cells are microtubules, microfilament and intermediate filament. 

                  2. Helps in intercellular and intracellular transport and provide mechanical supports to cytoplasm. 

                  3. Keep cell organelles in position. 

                  4. Formation of nuclear membrane and cell membrane. So, called membrane factory of cell. 

                  5. Formation of  

                    1. Vacuoles, 

                    2. Lysosomes, 

                    3. Glyoxysome, 

                    4. Golgi bodies, 

                    5. Exine of pollen grain. 

                    6. ImportantZymogen (IOM 2009) 

                  6. Detoxification of toxic substance. 

                    1. Organelle of Detoxification. 

                  7. The major phospholipid synthesized in ER is Lecithin (Phosphatidylcholine). 

              2. Golgi bodies 

                1.  

                   

                   

                2. Discovered by Camillo Golgi from nerve cell of cat 🙀 and Barn owl. 

                3. Also called Idiosome/ Dalton complex/ Middle man of cell. 

                  1. 1st stained GB by using Sudan III. So, also called Baker's bodies. 

                  2. Dictyosome is the name of golgi body but it is used only in Plant cell. 

                4. Absent in 

                  1. All prokaryotic cell 

                  2. Some Eukaryotic cell 

                    1. RBCs 

                    2. Sieve tube 

                    3. Sperm of Bryophyte and Pteridophyte 

                    4. Cells of Fungi 

                5. Formed from Vesicles of SER. 

                6. Consists of  

                  1. Cisternae (parallely arranged) 

                    1. New cisternae are constantly formed by budding off SER and fusion of vesicles. This outside convex known as 'Forming face'. 

                  2. Tubules and  

                  3. Vesicles. 

                7. Microtubules are never found in Golgi body. 

                8. Golgi apparatus is said to be  

                  1. "Principal director of macromolecular traffic 🚥 in cell". 

                  2. Middle man of the cell. 

                9. Maximum number of golgi bodies are found in Rhizoidal cell of Chara. 

                10. Golgi complex is involved in the formation of Zymogen granule. 

                11. Function 

                  1. Helps in secretion and storage of secretions. 

                  2. Chemically modify and transport the materials received by it. 

                  3. Cell plate 🍽 formation during cytokinesis. 
                    Note: Vesicles of Golgi bodies and Spindle protein form Phragmoplast. 

                  4. Helps in formation of lysosome. 

                  5. Formation of Acrosomes in sperms. 

                    1. Acrosome helps in penetration. 

                  6. Secretion of Mucilage in root tip region. 

                    1. Mucilage helps in lubrication. 

                  7. Formation of special type of carbohydrate called Sialic acid found in cell membrane. 

                  8. It helps in formation of 

                    1. Yolk, 

                    2. Melanin granules,  

                    3. Hemicelluloe, 

                    4. Galactose. 

                  9. It helps in   Glycosidation and Glycosylation. 

                    1. Lipid+CarbohydrateGlycosidation Glycolipid
                       

                    2. Protein+CarbohydrateGlycosylation Glycoprotein  
                       

                    3. Note: 

                    4. Glycosidation and Glycosylation are first started in ER. 

                    5. All complex carbohydrate except Glycogen are synthesized by GB. 

                    6. Protein packaging. 

                  10. Special point 

                    1. Common enzyme of ER and GB 

                      1. Peptidyl transferase = Main enzyme of RER 

                      2. Glycosyl transferase = Main enzyme of GB 

              3. Vacoles 

              4. Microbodies 

                1. Lysosome 

                  1. ImportantAcid phosphatase is the marker enzyme of Lysosome. 

                  2. The Lysosome are 

                    1. Produced by Golgi bodies, 

                    2. Eats Vacuoles and  

                    3. Associate with Endoplasmic reticulum for Excretion. 

                2. Peroxisome 

                  1. Photorespiration 

                3. Glyoxysome 

                4. Sphaerosome 

                  1. Plant Lysosome. 

                5. Lomasomes 

                  1. Fungi 

            4. Organelle without membrane 

              1. Ribosomes 

                1. Discovered and named Ribosome by Palade. 

                  1. So also called Palade particle. 

                2. Also called  

                  1. Engine of the cell 

                  2. Protein factory 🏭 of the cell 

                  3. RNP (Ribonucleo protein particle) 

                3. Smallest, unmembranous, Electron microscopic and Most abundant cytoplasmic organelle. 
                  Note: The smallest membrane bounded cell organelle is Lysosome. 

                4. Made up of r-RNA and Protein. 

                                                               
                   
                  Synthesized in Nucleolus   Synthesized in Cytoplasm
                   

                5. Ribosomes are formed inside Nucleolus. 
                  Note: Ribosomal factory of cell is Nucleolus. 

                6. Measuring unit of Ribosome = Svedberg unit (S) 
                  S

                  Sedimentation coefficient (Rate of settlement) [i.e., 1 S = 10-13 sec] 

                7. Ribosomes are isolated from other cell organelle by Fractionation and Ultra centrifugation. 

                8. Ribosome helps in Protein synthesis. 

                9. Found in both prokaryotes and eukaryotes except RBC and Sperms. 

                10. Types of Ribosomes 

                  1. 70s ribosomes 

                    1. Found in Prokaryotic cell and in Mitochondria and Chloroplast of Eukaryotic cell. 

                    2. Sub-units 

                      1. 30s (has single r-RNA) 

                      2. 50s (has two r-RNA) 

                    3. Note: 

                      1. Total r-RNA in 70s ribosome = 3 and Total proteins = 55 proteins. 

                      2. 55s ribosomes is found in mammals mitochondria not 70s and 55s has sub-units 35s and 25s. 

                  2. 80s ribosomes: 

                    1. Found in Eukaryotic cell 

                      1. Free = Synthesize non-secretory, non-export protein 

                      2. RER = Synthesize secretory export protein 

                    2. Sub-units 

                      1. 40s = has single r-RNA 

                      2. 60s = has 3 r-RNA 

                    3. Note: 

                      1. Total r-RNA in 80s ribosome = (1+3)=4 and total protein = 80 proteins. 

                      2. Two ribosomal sub-units are joined by Mg++. 

                      3. When Mg++ concentration is increased 10 times 2 ribosome combine to form dimer. 

                      4. During protein synthesis no. of ribosomes (6 to 8) are found to attach with m-RNA and polysome/ polyribosome/ Ergasomes. 

                      5. During protein synthesis smaller subunits of ribosome attach to m-RNA not the bigger one. 

                      6. Ribosomes are also found in organelle of eukaryotic cells like plastids, mitochondria and nucleus. So ribosomes are  also called Organelle within organelle. 

                11. To DoWhich of the following is/are electron microscopic? 

                  1. To DoDNA 

                  2. To DoRibosomes  

                    1. DNA and RNA are observed by X-ray crystallography. 

                  3. To DoRNA  

                  4. To DoAll 

              2. Centrioles 

              3. Cytoskeleton 

                1. Microtubules         

                2. Microfilaments 

                3. Intermediate filament 

              4. Nucleolus 

              5. Chromosomes 

          2. Cell Inclusions 

            1. Reserve food 

              1. Carbohydrate 

              2. Fats 

              3. Proteins 

            2. Secretory substances 

              1. Colouring matter 

              2. Enzymes 

              3. Nectar 

              4. Pigments 

            3. Excretory substances 

              1. Alkaloids 

              2. Glucosides 

              3. Tannins 

              4. Gum 

              5. Resins 

          3. Cytosol 

            1. Clear optically homogenous fluid portion of cytoplasm after removal of cell organelles and cell inclusions is known as Cytoplasmic matrix/ Cytosol/ Hyaloplasm or Ground plasm. 

            2. The ribosome containing ground substance is called Ergastoplasm. 

        2. Nucleus  

          1. Robert Brown discovered Nucleus from Root cells of Orchid. 

          2. Hammerling proved that nucleus is control centre of cell on the basis of his grafting experiment on Acetabularia. 

          3. Nucleus is also called Controlling centre of Cell/ Brain 🧠 of Cell/ Director of cell/ Apparatus of heredity. 

          4. It is not considered as an organelle. 

          5. Largest extracytoplasmic component of cell. 

            1. QuestionNote: The smallest component being Microfilament. 

          6. No. of Nucleus/cell as follows: 

            1. Uninucleated cell = Common 

            2. Binucleated cell = 

              1. Paramecium = Dimorphic nucleus 

              2. 2o mycelium of Ascomycetes and Basidiomycetes 

            3. Multinucleated cell = 2 types 

              1. Syncyte: Produced due to fusion of many cells. 

                1. Examples 

                2. Bone marrow 

                3. Striated muscles 

                4. Ascaris (Epidermis) 

              2. Coenocyte: Formed by repeated nuclear divisions without corresponding cytoplasmic divisions. 

                1. Hyphae of Phycomycetes 

                2. Xanthophyceae 

                  1. Vaucheria 

                  2. Botrydium 

                3. Latex cells 

            4. Anucleated cell: Cell without nucleus 

              1. Examples 

              2. Plant = Sieve tube at maturity 

              3. Animal = Mammal's RBC (Exception: Camel 🐫, Ilama) 

          7. Structure of Nucleus 

            1. Nuclear envelope/ Karyotheca/ Nuclear envelope: 

              1. Double layered, lipoproteinaceous. 

              2. Inner nuclear membrane is smooth as it lacks ribosome. 

              3. It separates nucleoplasm from cytoplasm. 

              4. The space between two nuclear membrane is called Perinuclear space (50-70

                Ao
                ). 

              5. Having pores (pore complex) which is Octagonal. 

                1. In the pore there is the presence of gates know as Annulus which allow only certain substances to go out through nuclear pore. 

            2. Nucleoplasm/ Nuclear sap/ Karyoplasm/ Karyolymph: 

              1. Includes nucleotides and different ions (Mn++, Mg++). 

              2. Cyclosis is absent as its viscosity is not constant. 

            3. Nucleolus/ Plasmosome: 

              1. Fontana discovered Nucleolus but term given by Bowman. 

              2. It is membraneless structure and also called "Ribosomal factory of the cell". 

              3. Largest part of nucleus. 

              4. It is colloidal mass and contains 

                1. rRNA,  

                2. Non-histone acidic proteins but has no DNA. 

              5. The shape of nucleolus is maintained by Ca++ and Mg++. 

              6. Biogenesis of nucleolus occurs at 2o constriction-I of SAT chromosome. 

            4. Chromatin 

              1.  

                 

              2.  

                Diagram of a replicated and condensed metaphase eukaryotic chromosome. (1) Chromatid – one of the two identical parts of the chromosome after S phase. (2) Centromere – the point where the two chromatids touch. (3) Short arm (p). (4) Long arm (q). 

                 

                 
              3. Term Chromatin was given by Flemming. 

              4. Name Chromosome by Waldeyer. 

              5. Made up of DNA (acidic, -ve charged) and histone protein (basic, + charged). 

              6. In ultrastructure, chromatin appears like beads on a string. 

                1. Beaded structure is known as Nucleosome. 

                2. Each Nucleosome has 8 histone molecule (i.e., 2 copies of 4 types). 

                  1. 4 types are 

                  2. H2A, 

                  3. H2B 

                  4. H3 

                  5. H4 and  
                    coiled by double stranded DNA.  

                  6. Core or nucleosome made up of histone protein is known as Nu body. 

                3. Two nucleosomes are joined by linker DNA. 

              7. Stain of chromatin/ chromosome is Feulgen stain = Basic fuschin 

                1. Feulgen stain exactly reacts with "Deoxyribose". 

              8. Euchromatin 

                 

                Heterochromatin 

                Light stain 

                Decondensed DNA 

                Active gene 

                Early replicated in S-phase 

                Dark stain 

                Condensed form 

                Inactive gene 

                Late replicated in S-phase 

              9. Chromosome 

                1. No. of Chromosome 

                  1. Smallest no of chromosome in  
                    Haplopappus gracillis. 

                     

                    Largest no of chromosome in 
                    Ophiglossum (Pteridophyta) 

                2. Condensed form of chromatin is called Chromosome. 

                3. ImportantA chromomere, also known as an idiomere, is one of the serially aligned beads or granules of a eukaryotic chromosome, resulting from local coiling of a continuous DNA thread. Chromeres are regions of chromatin that have been compacted through localized contraction. 

                  1. Meiotic chromosome having beaded structure is known as Chromomere. 

                4. Haploid set of chromosome is called genome. 

                5. Chromosome is the physical basis of inheritance. 
                  Note: DNA is the chemical basis of inheritance. 

                  1. Chromosomes are filamentous structure which carry hereditary units (genes) and hence called vehicle/ bearer of genes. 

                6. Chromosome theory of inheritance was proposed by Sutton and Boveri respectively. 

                7. Morphological feature of chromosome of a species is called Karyotype. 

                  1. Diagrammatic representation of karyotype in descending sequence is called Idiogram. 

                8. Differential staining of the chromosome due to differential thickening is called Heteropycnosis. 

                9. Saliva test in olympic games is related to X-chromosomes (Barr bodies). 

                10. Ultrastructure of an Eukaryotic chromosome 

                   

                   

                  1. Pellicle: It is sheath or covering of chromosome. 

                  2. Matrix: Ground substance 

                  3. Remember for laterChromonemata: Coiled threads which form the bulk of chromosomes. 

                  4. Primary (1o) constriction/ Centromere:  

                    1. Narrow non stainable area where 2 chromatids are attached. 

                    2. It provides site for spindle attachment. This site (point) is known as Kinetochore. 

                    3. The main difference between centromere and kinetochore is that the centromere is a DNA region whereas kinetochore is an assembling protein complex in the centromere. 

                    4. The centrosome is an organelle that serves as the organizing centre of all microtubules in an animal cell 

                      1. Types of Chromosome on the basis of position of centromere 

                      2.  
                        1. Acentric chromosome 

                        1. Metacentric chromosome 

                        1. Submetacentric chromosome 

                        1. Acrocentric chromosome 

                        1. Telocentric chromosome 

                         
                        1. Holocentric/ Polycentric/ Diffused centric chromosome 

                        • Chromosome without centromere 

                        • Centromere in middle i.e., at the centre 

                        • Arms are of equal size. 

                        • Anaphasic stage 

                        • 'V' shaped 

                        • Centromere submedian i.e., near to centre. 

                        • Anaphasic stage. 

                        • 'L' shaped. 

                        • Centromere subterminal i.e., near to top. 

                        • Anaphasic stage. 

                        • 'J' shaped. 

                        • Centromere terminal; Anaphasic stage. 

                        • Only one arm or chromosome with single arm. 

                        • 'I' shaped or rod like. 

                        • Whole surface functions as centromere 

                        • E.g: Lujula 

                         

                         

                         

                         

                         

                         

                         

                        1. Shape of chromosome is best studies in Anaphase. 

                        2. Structure, morphology, size, number, etc. can be best studied in Late Prophase and Metaphase (More appropriate metaphase). 

                        3. The ratio of length of the two arms of chromosomes is called centromeric index. 

                  5. Secondary (2o) constriction-I: 

                    1. Also known as NOR (Nuclear Organiser Region) 

                    2. Biogenesis (formation) of Nucleolus is at 2o constriction-I of SAT chromosome in telophase. 

                    3. Contains genes for transcription of r-RNA. 

                  6. Secondary (2o) constriction-II: 

                    1. It contains genes for transcription of t-RNA. 

                  7. Satellite/ Trabant:  

                    1. Knob like structure near to 2o constriction-I is called satellite. 

                    2. The chromosome bearing satellite is called SAT chromosome. 

                      1. When SAT chromosome contain secondary satellite then it is called Tandem SAT. 

                    3. There are at least 2 SAT chromosomes per diploid nucleus. 

                  8. Telomere: 

                    1. It is terminal end/seal end of chromosome. 

  10. Notes 

    1. Skeletons of Cell 

      1. Exoskeleton = Cell wall 

      2. Endoskeleton = Endoplasmic reticulum 

      3. Cytoskeleton = Microtubules, Microfilaments and Intermediate filaments 

    2. Sizes 

      1. Largest 

        1. Largest cell component = Nucleus 

        2. Larges cell organelle (In plant) = Chloroplast 

        3. Largest cell organelle in animal = Mitochondria 

        4. 2nd largest cell organelle in plant = Mitochondria 

      2. Smallest 

        1. Smallest cell organelle = Ribosome 

    3. Semi-autonomous organelles 

      1. Contains  

        1. DNA, 

          1. DNA is simple, circular, double stranded. 

        2.  RNA,  

          1. Ribosomes are 70s type. 

        3. ribosomes. 

      2. Replicate independent of Nuclear DNA. 

      3. Plastids 

        1. Plastids carrying genetic information is called Plastidome. 

      4. Mitochondria 

        1. These are called Endosymbionts of cell or Prokaryotic cell within eukaryotic cell or cell within cell. 

        2. To DoBiogenesis: Mitochondria divide by binary fission to form new ones due to DNA. 

        3. ImportantDefinitionApoptosis is programmed cell death caused by DNA of Mitochondria.